1. Field of Invention
The present invention is directed to vehicular or automotive side, rear view mirrors, and in particular to an auxiliary refractor for such mirrors, comprising for example a prism, which when applied, or located adjacent, to the mirror modifies the mirror's field of view by refracting the reflected light in such a manner as to widen the effective field of view of the mirror. The present system is intended to be used in conjunction with the side automotive rear view mirrors, including particularly the driver's side and also, if desired, the passenger's side, as well as the interior mirror.
2. Prior Art & General Background
There have been many attempts in the past to modify rear view mirrors to change their field of view.
A list of prior patents which may be of interest are listed below:
______________________________________ Patent No. Patentee(s) Issue Date ______________________________________ 2,763,187 H. Wiener Sept. 18, 1956 3,104,274 G. W. King Sept 17, 1963 3,267,806 Keij Azegami Aug. 23, 1966 3,501,227 W. J. Landen March 17, 1970 3,712,715 Carl E. Wagner Jan. 23, 1973 3,797,920 Theodore L. Beach March 19, 1974 3,972,601 William Johnson Aug. 3, 1976 4,200,359 David Lawson April 29, 1980 4,223,983 Stephen Bloom Sept. 23, 1980 4,311,363 Joseph Marsalka Jan. 19, 1982 RE 30,673 William Feinbloom July 14, 1981 Foreign Patents: West Germany 2,425,502 Marhauer December 1975 2,701,817 Muller July, 1978 2,756,573 Brunner July, 1978 3,525,261 Stein November, 1985 ______________________________________
The above cited prior art may be generally divided into three catagories:
(1) Those patents directed to the addition of a supplemental, relatively small mirror placed at an angle on the rear view mirror (U.S. Pat. Nos. 4,200,539; 4,311,363 and 4,223,983);
(2) Those directed to the addition of a curved (either convex or concave) supplemental mirror on the main rear view mirror (U.S. Pat Nos. 3,104,274 and 3,267,806); and
(3) Those directed to two or more flat mirror sections juxtaposed to give deferring angles of view (U.S. Pat. Nos. 3,712,715; 3,797,920; and 3,792,601).
The first cited group above is more directly pertinent to the preferred embodiments of the invention, while the second group has only secondary interest, and the third group is merely included for general background information.
In the three patents cited in the first group above, a flatter, curved mirrored surface is supported on the main mirror surface at an angle in order to change the field of view to expose the "blind spot" of the rear view mirror.
Only Feinbloom appears to relate (although unclearly and in very small part) to transmission and refraction of light into a wedge-configured medium, as opposed to a surface-type reflection from the angled exterior surface, as disclosed through out the prior art. For reasons discussed below, Feinbloom is clearly distinguishable from the present invention.
In contrast, the present invention uses a refractive technique, in which the light passes into the structure and is reflected off the back surface, with the refraction causing the difference in the angle of the field of view. It is apparent, based upon careful review of the prior patents cited above, that none of the previous patents contemplated the utilization of refractive technique in the area contemplated in the present invention.
In addition, the present invention offers the advantage of increased clarity of the additional field of view over that offered in the prior art. For example, U.S. Pat. Nos. 3,267,806, 4,311,363 and 3,104,274 both offer wide angle views, but at the expense of a spherical aberration, which greatly distorts the angled view, to such a point that it becomes difficult to actually ascertain the location of any objects of the view and their distance from the driver.
With regard to the Feinbloom '673 patent, it is respectfully submitted that the disclosure, a reissue patent, is defective and lacking to the point where it is insufficient to teach one of ordinary skill in the art to which the invention pertains how to make and use the invention without undue experimentation and thus does not fulfill the requirements of the first paragraph of 35 USC 112.
It appears that the Feinbloom originally sought to claim an angled mirror attachment to vehicular side view mirrors, but for whatever reason was unsuccessful.
The reissue patent also apparently only scantly "disclosed" an alternative embodiment teaching the utilization of a "prism" in a single top view drawing (FIG. 4) in conjunction with a mirror, but does not disclose how to make and use the invention. Indeed, the little verbiage citing FIG. 4 is contrary to accepted teachings in optics; further, it is apparent that the "prism" embodiment recited in FIG. 4 and taught in the application was a defective afterthought. It is for this reason Feinbloom is grouped in the first category discussed above.
The '673 patent in fact, while entitled "Side View Mirror Employing Prism For Blind Spot Correction", only has one relatively short disclosure paragraph in the entire patent relating to the prism/mirror embodiment, with the rest of the disclosure devoted to angled mirror accessories for enlarging the users field of view. This is ironic, because the principle teachings of the patent do not relate to refractive optics at all, and in fact does not even mention refraction.
In fact, if one of ordinary skill were to rely on the disclosure for making and using the invention, not only would there be required much undue experimentation, but the person would only have the figure to rely upon, as the written disclosure relating to the figure is incorrect and inconsistent, for the reasons discussed infra. The mere scanty, top view figure would be insufficient for one of ordinary skill to reduce the invention to practice in a satisfactory manner, as shown more fully below.
With regard to the Feinbloom discussion of the FIG. 4 embodiment (column 5, line 14--33), optics does not teach any concept cited by Feinbloom as "base angle".
The side of the prism which subtends the apical angle is called the "base". The Principles of Ophthalmic Lenses, M. Jalie, Haxell & Vinney, Ltd. (G.B.; 4th Ed. 1984).
The deviation produced by a prism depends upon its apical angle and its refractive index. id.
From OPTICS by A. H. Tunnacliffe and J. G. Hirst (printed in Great Britain by the Eastern Press, Ltd., 1981 and reprinted 1983), the index listings under angles are:
______________________________________ Apical of reflection Brewster's of refraction critical solid of incidence ______________________________________
From Mosby's Comprehensive Review Series "Review of Refraction" Jack Hartstein M.D., Copyright 1971, by the C. V. Mosby Company, printed in U.S.A. (St. Louis):
"Definition of a Prism: A prism is an optical medium formed by two sides that are plane but not parallel. In the simplest form of a prism as used for refraction, the two refracting surfaces need to be considered--the light entering the prisms at the first surface and leaving at the second. The point of intersection of these two surfaces is the apex, or refracting edge, of the prism. Any section through the prism perpendicular to one of the refracting surfaces is a principal section, and the apical angle is the refracting angle. The prism will permanently change the direction of the rays, but, for practical purposes, will not change their relationship toward each other."
If one were to guess at what Feinbloom's "base angle" might be, using a right angle prism as an example, one would logically deduce that:
The right angle A is constant at 90 degrees, and the apex B is the narrowest part of the prism. The only angle left would be the point at which the base meets the hypotenuse. One would then conclude that this must be what is referred to as the "base angle" C.
If this is the case then we can determine the value of the apical angle in a prism with a "base angle" of sixteen degrees.
If A is 90 degrees and C is 16 degrees, then from basic geometry B must be 74 degrees.
It is impossible to determine the exact angle of deviation, since Feinbloom's description gave no "index of refraction" of the medium used. However, generally with prisms of large apical angle "if the angle of incidence on the first face of a prism is small, then it follows that the angle of incidence inside the prism at the second surface will be large, assuming that the apical angle of the prism is sufficiently large. This situation provides the possibility for total internal reflection to occur at the second face of the prism, for if the angle of incidence at the second surface exceeds the value of the critical angle, then no light will be refracted out of the second face of the prism." Optics, A. H. Tunnacliffe & J. G. Hirst; supra.
It can thus be concluded that this is a prism through which no light can pass in the described fashion.
The sentence "A prism will provide the angle of sixteen degrees if the base angle is sixteen degrees" is inconclusive, confusing and erroneous, since to determine the angle of deviation (which is not mentioned) of a prism, one must know the apical angle of the prism and the index of refraction of the medium being used (which also is not mentioned.)
Since the term "base out" is written in quotation marks, one can assume that some special significance should be attached to it.
In opthamalmic practice prisms are often used to correct a "phoria" (Mosby's Review of Refraction, Jack Hartstein, M.D.; supra) defined as a tendency to turn the eyes from parallelism--in, up, out or down. This is often achieved by situating prisms over the independent eyes in what in the ophthalmic trade has referred to as, base in, base out, base down, base up, or a combination depending on the type of phoria involved (orthophoria, esophoria, exophoria, etc.) The term "base out" refers to the prism's apex to base axis placed between the patient's nose and temple with the base at the temporal side. So "base out" prism in the patient's left eye would place the base of the prism to the left. However, base out prism over the patient's right eye places the base edge of the prism to the right.
It would appear as if Feinbloom is using the terminology of one art to describe a different art in a way that does not properly communicate a meaningful concept.
This is consistent with the assertion above that the prism embodiment was inserted as an incomplete, defective, afterthought, and explains why the disclosure was so scanty and flawed. It thus appears that Feinbloom had no idea as to how to reduce the invention to practice, much less enable the specification to teach one of ordinary skill how to make and use the invention.
Additionally, whatever else may be said of the Feinbloom disclosure, the scanty "disclosure" of the FIG. 4 drawing, particularly in the context of FIGS. 2 & 3, would lead one to put the "prism" section, whatever it might be, in the upper section of the mirror straddling across its central portion. Whatever image it would produce, it would be difficult for a viewer to put it into context with the mirrored image and be meaningful and useful.
As opposed to Feinbloom, the present application teaches in very specific terms how to make and use the invention, including the selection of the appropriate refractive medium, calculation of the apical angle, location and positioning of the system, etc. In short, it enables one of ordinary skill to make and use the invention, as required by the federal patent laws.
With regards to Marhauer, applicant is unable from its abstract to decipher the inventive concept underlying the cited patent. However, the drawings appear to indicate angled reflective means of providing an increased field of view, and not the refractive prism means as contemplated in the present invention.
The Landen patent is likewise fully distinguishable, but for a different reason. Landon contemplates a means of enlarging a field of view different from that contemplated in the present invention, which addresses the field of refractive optics, as opposed to angled mirrors (class 1 addressed above).